Switch protection for block-signal systems



Dec. 11 1923. 1,476,866

S. N. WIGHT SWITCH PROTECTION FOR BLOCK SIGNAL SYSTEMS Filed Nov. 3, 1920 5 Sheets-Sheet 1 WES By 470 33, Q I y ATTORNEY Dec, 11 1923. 1,476,866

S. N. WIGHT SWITCH PROTECTION FOR BLOCK SIGNAL SYSTEMS 'Filed Nov. 5, 1920 5 Sheets-Sheet 2 Dec. 11 1923. 1,476,866

s. N. WIGHT SWITCH PROTECTION FOR BLOCK SIGNAL SYSTEMS 5 Sheets-Sheet 5 Filed Nov. 5, 1920 A'IYTORNEY @JZZ Dec. 11, 1 3.

S. N. WIGHT SWITCH PROTECTION FOR BLOCK siGNA-L SYSTEMS 5 Sheets-Sheet 4 Filed Nov. 5, 1920 Dec. T1 1923.

1,476,866 s. N, WlGHT SWITCH PROTECTION FOR BLOCK SIGNAL SYSTEMS Filed Nov. 5, 1920 5 Sheets-Sheet 5 FIG. 6.

3 A T'TORNE Y.

Patented Dec. 11, 1923.

UNITED star-as Parana caries.

SEDGWICK N. WIGHT, OF ROCHESTER, NEW YORK, ASSIGNOB. TO GENERAL RAILWAY SIGNAL COMPANY, OF GATES, NE)? YORK, A CORPORATION OF NEW YORK-- SWITCH PROTECTION FOR BLOCK-SIGNAT SYSTEMS.

Application filed November 8, 1920. Serial No. 421,453.

To all whom it may concern:

Be it known that I, Snocwrcn N. IGHT, citizen of the United States, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Switch 'Protections for Block-Signal Systems, of

which the following is a specification.

This invention relates to block signaling systems for railroads, and more particularly to the protection of outlying switches in block Signal territory.

In accordance with the present practice with which I am familiar, switch indicators are provided at the outlying switches in block signalterritory for the purpose of informing the trainman when it is safe to open the switch. The protection afforded by such switch indicators evidently depends upon the care observed by the trainman in obeying the indications. If he is thoughtless or careless, it is possible for him to open a switch when a train is approaching at high speed on the main track, with the result that an accident occurs. In accordance with the present invention it is proposed to provide a check on the human factor by employing a switch lock in connection with the switch and by controlling this lock in such a way that the trainman cannot open the switch except when it is safe to do so.

The general objects of the invention are to provide an arrangement of devices and controlling circuits for switch locks which will give desired protection without interfering with normal train movements or causing unnecessary delay. Other specific objects and advantages of the invention will appear as the description progresses.

In describing the specific embodiments of my invention in detail, reference will be made to the accompanying drawings, in

which- Figure l is a diagrammatic view'showing myimproved system for the control of switch locks applied to an outlying switch on a stretch of double track;

Fig. 2 is a view, partly in perspective with ,parts broken away and spread apart for clearness, which shows one form of an electrically operated switch lock adaptable for use in connection with my inventlon;

Figs. 3 and 4 when placed end to end,

block signal system, commonly known as an absolute permissive block system, suitable for single track operation of trains, together with an outlying switch squipped with my improved switch lock control, system;

Fig. 5 is a view similar to Fig. 4 showing a modified arrangen'ient of the controlling circuits for the switch lock for single track roads; and

Fig. 6 illustrates a still further modification.

In connection with my invention I employ an electrically operated switch lock which may be of any suitable construction. One type of such a switch lock is illustrated in a diagrammatic way in Fig. 2. Referring to Fig. 2, a lock rod 11 is connected in the usual way to the movable switch points 12-12- and is provided with a hole to receive a lock bolt 13 when the switch points are in the normal position shown, that is, are lined up for the main track. The lock bolt 13 is supported and guided by a suitable casing or framework 14, and is pivotally connected to a link 15. This link 15 is pivotally connected at its upper end to a crank arm 16 secured to a shaft 17. To the shaft 17 is fastened a lock plate 18 and an operating 'handle 19. The lock plate 18 is formed with a shoulder for cooperating with a lock dog 20 carried by an armature 21. This armature 21 is raised when the coilsor windings 22 of'a lock magnet L are energized. The armature 21 is also connected by a rod 23 to a shaft 24 which carries the usual miniature semaphore or indicator 25. In practice, the operating i The switch points 12 -12 which are in practice moved by some suitable switch stand 'be energizedbefore the switch can be op-,

erated. When the lock is released, this is indicated by the position of the indicator 25, and the handle 19 maybeswung to lift the lock plunger 13. Inthe type of electric lock illustrated, and which .is preferably employed, this handle 19 is moved so as to bring the crank 16 and link 15 on upper dead-center, so that the lock plunger is held up, while the trainman throws the switch points. In order to assure the replacingof the lock plunger, the door giving access to the handle 19 is, in the type of switch lock referred to, provided with lugs and recesses (not shown) .in such a way that the. door cannot be closed it this handle is left in its upright position. If, however, the handle is partly turned back tothe normal position shown, sufiicient to bring the link 15 beyond dead-center, then the door can be closed and locked. In ordinary usage, the trainman, after having unlocked and opened the switch, restored the handle 19 part way to its normal position, with the lock plunger 13. resting upon the lock rod 11, and closes and locks the door, and as Soon as the switch points are restored to the normal position. the lock plunger 13 drops by its own weight into the hole in the lock rod 11, the parts being thus restored to normal without special manipulation by the trainman. It is .to be understood,however, that this type of electric lock described is merely illustrative, and various other expedients may be employed for compelling manipulation of he lock in a certain manner in order to saieguard the handling of the switch. For the purpose of explaining the present invention, it. is not necessary to considerthe various modifications of the electric'lock structure that.

may be employed.

In Fig. 1 I have shown a-system for the control of the switchlock in itssimplcst form 2115 lied to a stretch of double track over w ich trafiic normally moves in one direction from left to right, as indicated by the arrow. The track rails 27 of this stretch are divided by insulated joints 28 into blocks or tracksections, asD, E, F in the usual way, each of these track sections being provided with'the usual track battery 29, and a track relay, as 30 to 34 inclusive. Traflic over this stretch is governed by signals 35 to 38 inclusive. The line relays and con trolling circuits for these signals, which may been shown in or er to avoid unnecessary complication of the drawing. To illustrate the prese'nt invention. it. is assumed that there is an outlying switch leading to a siding SD in the block Ebetween the signals 37 and 38; and in accordance with this invention, the block F, where this outlying.

switch is located, is prbvided with a short track section 13 adjacent to said switch. A switch box, having contacts '39 shown con -ventionally, is connected to the points of the switch in the usual way. To avoid com: plication in illustration, all parts of the switch lock shown in Fig. 2 have notbeen illustrated in Fig. 1, but merelv the lock magnet L, lock dog 20 and plate 18. In connection with the control of the lock magnet L I employ any suitable form of a time element relay T. Various types of time element relays, well known in the art, are suitable for this purpose. One device of this nature is disclosed, for example, in patent to R. C. Leake, No. 1,320,247, October '28,

1919. For simplicity I have illustrated the relay T as comprising a movable armature or contact finger lO connected to a suitable dashpot or time control device 41, so that when said relay is energized;- it will close its contacts after the lapse of a predeter-- mined time for which the device is set. In addition to the switch lockand time element relay T the improved system of switch proj tection'includes a push button PB or other suitable circuitcontrolling means, adapted to be operated by the trainman. This push button is shown diagrammatically and coin-v prises a number'of contact fingers 4.2, 43 and 4A wh chcooperate with suitable fixed contacts indicated conventionally as arrows.

This push button PB is located near the as shown can be traced from B to G, current will flow in this circuit.

The controlling circuit for signal '37, which is only in part illustrated, is controlled by the track relays' 32, 33 and 34 of the track sections F, F andF constitut ing the block between the signals 37 and 38. This controlling circuit also includes the switch box contacts 39, which are open when assesses the switch is shifted from the normal position to the reverse position. This controlling circuit for the signal 37 passes through the normally closed contacts 42 on the push button'PB. Thus, if a train is in any part ofthe block protected by signal 37, or if the push button PB is.operated,' or if the switch is open, the controlling circuit for signal 37 is broken and said signal is put to the horizontal or stop position.

The lock magnet L may be energized by any one of three circuits when the push button PE is operated. One circuit is from battery B through contacts 43 of the push button, wire 45, lock magnet L, wires 46 and 47, back contact of armature 48 of the track relay 33 connected to short track section F and thence throu h other wires and connections (not shown to the other terminal of the battery. Another circuit for energizing the lock magnet L is from battery B, contacts 43 of push button PB, wire 45, lock magnet L, wires 46 and 50, front contact of armature 51 of traclrrelay 32, wire 52, front contact of armature 53; of track relay 31, wire 54, and front contact of armature 55 of relay 30. Another circuit for energizing the lock magnet is from battery through contacts l3 ot the push button PB, wire 45, lock magnet L, wires 46 and 49, and contacts 40 of the time element relay T. The time element relay T is energized by a circuit which may be readily traced through contacts 44 of the push button PB when said push but-ton is operated.

The operation of the system shown in Fig. l is a follows: Assume that there is no train in the blocks D and E or in track section F. lVheri a trainman desires to open the switch leading to the siding SD, he operates the push button PB, opening contacts 42 and closing contacts +i3-4h The opening of-contact 42 breaks the control circuit for signal 37 and causes this signal to assume the stop position. This in turn re sults in putting the signal 36 to the caution position by virtue of the usual control circuits (not shown). This results in blocking train movements toward the switch. Since it is assumed that the blocks D, E and track section F are not occupied, the circuit through the front contacts of the track relay fill, 31 and 32, hereinbefore traced, is

established. and the lock'magnet L is energized. This releases the handle 19, so that the traininan may raise the lock plunger l3 and release the switch points. When the switch is opened, the switch box contacts 39 open and keep the signal 37 at stop, so that trains approaching the switches are blocked so long as the switch remains open. .llfhen the switch is reclosed, the lock plungil drops in place and locks: the switch poingkznclall the parts and circuits are rect. othe normal position shown.

, that there-is time for the train on the siding SD to get out on the main track, in which case it is desirable to release the switch lock provided the proper precautions have been taken. These conditions are taken care of by the time element relay '1. When the push button PB isoperated the energizing circuit for the relay T is closed at the contacts 44, and after the selected time interval for which said relay is adjustech'the contacts of this relay close, establishing a circuit hereinbefore traced for energizing the lock magnet L, regardless of the presence of the train in the blocks D or E.- As previously explained, operation of the push button PB puts the Signal 37 to stop in the stop position, and the signal 36 in the caution position. If a'train is in the block D' at the time the push button PB is operated, it will receive a. caution indication at the signal 36 and come to a stop at the signal 37 in the regular Way. The time interval required for the operation of the relay T is selected or adjusted so that, if the train is beyond signal 36, and the push button PB is operated and the operation of the relay '1 is commenced, such train will have time enough to either stop before reaching the switchor else get past this switch. Thus, before the lock magnet L can be energized, and the switch lock released, a warning must-be given to the train assumed to be on the track section D or E, and sufficient time elapse for this train to stop or proceed by the switch. If desired, a separate switch indicator may be provided according to the resent day practice atthe switch, so that t e trainman can tell if another train is approaching, without being required to operate the push button PB and put the signal 37 to stop, it being evident that it may be objectionable in some cases to put the signal 37 to sto in the face of a. train approachingat igh speed.

It often happens that a train on the main track will enter the siding SD, and it is necessary to make provision for releasing the switch lock under such conditions. When a train is to enter the siding SD, it pulls up to the switch on to track section F thereby dropping track relay 33 and closing its back contact, so that the lock magnet L can be instantly energized when the push button is operated. The track section F is preferably made only a few rail lengths so that a trainman at the switch could not fail to observe a train on this shorttracksectionn From the foregoing it will be observed that the control of the switch lock according to this invention'is such that the lock may be released immediately if a train has pulled up to the switch for the purpose of entering the siding, or if there is no approaching trainwithin a certain distance of the switch, this distance being suflicient to bring such approaching train to a stop be- .fore reaching the switch. i\lso, in special cases where it-may be desirable to be able to open the switch, although a train is withinthe limits of protection, the switch lockmay be released after a time, this time interval being suchthat the train, it it continues its movement, will have time enough to get by theswitch, or else to stop in obedience to the signals.

'- In Figs. 3 and 4 thereis shown a system of control for the switch lock of an outlying switch on a single track on which-traffic is in both directions. .In Figs. 3 and 4 there is -illustratedin a conventional way a complete system suitable for governing tratlic over a stretch of single track between two passing sidings, together with the circuits and deices relating to the control of the switch lock combined with this system. It is to be understood, however. that the particular application shown is illustrative of only one embodiment oi the means contemplated by this invention, and that theinvention can be applied to single track signaling systems of other types in the same way.

The block signal system shown in Figs. 3

' and 4.- is of the type commonly known as an absolute permissive block system; and is shown and described in detail in my prior Patent, 1,294,736, 1*cbruary-18. 1919, so that for the purpose of explaining the present invention, only a brief description o't this APB system will be given.

Figs. 8 and 4 .are to be arranged end to end with Fig. 4 on the right. 'The stretch of track between the two passing sidings PS and PS is divided in the usual way into a number of track sections, which have been designated a, Z), etc. Each of these track sections is provided with the usual track battery and track relay. In order to avoid 001- plieation of the drawing, these; track relays have been illustrated"conventidnally as dash lines connected to the traclcrails. the contact fingers ofeach track rela'y being shown in practice made distinguishable from the other signals by having square ended blades and marker lights.

The system in a general way is made up of a number of units, and for convenience the relays and other devices of each unit are given the same reference characters with exponents corresponding to the signal associated with that unit. At each signal is a line relay, as H a sticlrrelay, as S and a local battery. in some cases the circuits connected to the local batteries are entirely local, and in this case these circuits are des 'ignated conventionally as terminating at: symbols B and N. In other cases the local batteries transmit current iron'i one signal location to another. the return connection in each instance being made by .a common wire extending along the track, and in this case, the circuits are indicatedconvention ally as terminating at the symbols B and C. Operated by some of the signals is a pole changer, 1. This pole changer, being of well known construction, has been illustrated conventionally, and it is understood that .it is coupled in some suitable way to the operating mechanism of the corresponding signalso as to be shifted from the position shown to -the opposite position when the signal changes from its caution to the stop position. The signals are also provided with suitable circuit controllers, as 0 which have been shown in accordance with established convention. trollers are closed when the corresponding signal is in the 90 or proceed position, and

for part of its movement (usually about toward its zero degree or stop position.

To illustrate the nature and mode of operation of my improved system of control for switch locks, it i s assumed that there is an outlying switch somewhere in the stretch of single track which leads to the siding SD. This switch may be located at any point in the stretch, and the same principles of control hereinafter explained may be employed by making appropriate changes in the wiring connections.

In considering the devices and circuits constituting the present invention, it is (le sirable to explainbriefly the operation of the APB system, reference being made to my priorpatent above mentioned for .a fuller explanation of some of the special features and advantages of this type of system. Before talEing up the description of this operation, it is convenient to point out some of the typical circuits involvedin this operation. The indications of each signal are controlled by neutral and polar contacts Forexample, referring to the signal 2, the 90 on the corresponding line, relay.

controlling circuit (which puts the signal in the 90 or proceed position) ma be traced as follows: from battery through These circuit con iii) neutral armature 70 of the line relay H Wires 71 and 72, polar armature 73, wires 74, signal 2 to N, signifying a connection to the other terminal of the battery. The circuit for controllingthe 45or caution position of the signal 2 may be traced from battery B, neutral armature '70, wires 71 and 75 and signal 2. The circuit controlling the line relay H controlling circuits for the other line relays. This circuit may be traced as follows: commencing at the connection to the common wire C, relay H wire 76, front contact 77 of the track relay of section 6, wire 78, front contact 7 9 of the track relay of section a, wire 80, back contact 81 of stick relay S wires 82 and 83, front contact 84 of line relay H, wires 85 and 86, and through the pole changer P to the common wire C.- The front contact 84 of the line relay H is shunted when the stick relay S is energized, said shunt comprising wires 83 and 87 front contact 88 of the stick relay S", and wires 89 and 85'. From the foregoing circuit, it will be evident that the line relay H is 'deenergized when (1) either of the track sections 1) or c is occupied, (2) stick relay S is energized, (3) line relay H is deenergized, and stick relay 8* is not energized at the time. The line relays of signals 4 and 6 are controll d hy the line relay' of the signal next in advzlric'e, in the same way.

The stick relay at each signal is energized when a train passes that signal in the direction of trafiic governed thereby, and is main tained energized until such train has passed out of the track sections governed by that signal. For example, the pickup circuit for the stick relay S may be traced as follows: from battery through circuit controller-O wire 90, back contact 91 of track relay section (1, wires 92 and 93, relay 8, to the other terminal of the battery. when a train traveling from left to right, enters the track section d, back contact 91 of track relay of that section is closed, thereby establishing this pickup circuit during the time the sig nal is moving to its sto position. The stick circuit for the relay may be traced as follows: commencing at battery 'B, hack contact 94 of line relay H wire 95, front contact 96 of relay S, and wires 97 and 93 through said relay to the other terminal of the battery. Thus, the stick relays, when once energized, are maintained energized so long as the corresponding line relay is deenergized.

Assume a train enters the stretch of single track from the siding PS, traveling from left to right in the direction indicated by arrow X. The entrance of this train into track section 6 drops the line relay H and thereby putting the signal 2 to stop. At the same time stick relay S is energized, so as to modify the control of the signal (not.

is representative of the ping of line relay H in turn causes drop- 7 ping of line relay H, which in turn drops line relay HZ thereby utting all of the op posing signals 3, 5 and to stop. The start ing signal 7 being at stop, blocks the en trance of another train into the opposite end '7 of the stretch of single track. As the train proceeds into track section a, the same conditions are maintained. When this train enters track section (1, signal {1 is put to stop,

and stick relay Spicked up. The picking up of stick relay S shunts the front contact 84 of line relay H so that as soon as the train leaves the track sections 6 and 0, line relay H is picked up, and the signal 2 al lowed to assume its 45 orcaution position,

the polarity of the control circuit for this line relay having been changed by pole changer P when signal 4 went to stop. When the train passes beyond signal 3, this signal clears, providim there is no following train within the imits of its control. As the train proceeds, a similar operation is repeated, the several signals behind this train assuming the caution position and then the proceed position. The same operation occurs for. movements in the opposite direction from right to left. I

The controlling circuits for the lock magnet L in Figs. 3 and 4, while similar in principle to those already described in connec W0 tion with Fig. 1, are somewhat different be;- cause trains may approach a switch from either direction. The switch is provided with switch box contacts 98 and 99 in the usual way, and the push button PB is provided with two normally closed contacts 100 and 101 and two normaly open contacts 1 2 and 103. The controlling circuit for line relay H of signal 6 (which can be readily traced from analogy to the circuits already no discussed) is taken throu h the switch box' contact 98 and the pus button contact 100, so that when said push button is dyerated, or the switch opened, the signal. 6 is caused to assume the stop position, the'sig- '11s nals 4c and 2 in turn being caused to move to the sto position. Similarly, the control circuit her the line relay H of signal 7 is taken through the push button contacts 101 and the'switch box contacts 99 for the same no purpose. The lock magent L may be energized by an one of three circuits, similar to those alrea y described in connection with Fig. 1. When the short track section g (corresponding to track section F in Fi 1) is occupied, and the push button PE is operated, t. on ma ent Lia ener ized by a circuit whic' may e traced as fol ows: commencin at B, back contact 104 of the track relay c section 9, wires 105, 106, lock mg m train isbetween track section 0 next in the rear of signal 4;, and track section is, next in the rear of signal 9. A train receding from' the switch, however, does not prevent energization of the lock magnet L, for

'- reasons about to be explained. The circuit for controlling the lock magnet L, depend? out upon the direction of movement and location of trains on'the trackway, comprises a main circuit and a number of multiple branches. The main circuit may be traced as follows: commencing at B (near signal 3) t'hrough front contact 111 of the track relay of section 0, wires 112 and'113, front contact 114 of track relay of section (1, wire115, front contact 116 of track relay of section e, wires 117- and 118, front 1 con-. tact 119, track: relay of section '1", wires 120 and 106, lock magnet L, wire 107, push buttoncontacts 103, wires 108, 121 and 122, front contact 123 of track relay section It,; wire 1 24, front contact 125 of track relay of' section igwires 126 and-127, and through front contact 128 of track relay of section/'12,

to N. Frontcontact 111 is shunted, when stick relay S is picked up, by a shunt comprising wire 129, front contact. 1300f said stick relay, and wires 131 and 112.

neoted directly tobattery along wire 132 and front contact 133 of said relay. Similarly, when stickrelay S is picked up, wire 121 is connected direct to the other terminal N of said battery through wire 134 and front contact 135 of said relay; and when stick.

relav S is picked up wire 126 is connected to N over wire 136 and front contact 137 of.

said relay. 7

The third energizing circuit for the lock magnet L is established when the push but ton. PB is operated,- and the time element relay T has closed its contacts 138 and 139. This energizing circuit .may be' traced as follows: commencing at battery, contact 139, wires 14 0-and 106, lock magnet L, wire 107, push button contact 103, wires'108 and 141 and contact 138 of relay T to N. The time element relay T is energized when the push button P is operated through contact 102, by" means of a circuit readily traced on the drawing. k

The operation of the controlling system for the switch look, when applied to a single track railroad, and shown in Figs. 3 and 4,

v is as follows :If no train is approaching the switch from either direction, within the limits of control hcrcinbefore stated, the

lock'magnet L is energized immediately when the push button PB is operated.

When

stick relay S is picked up, wire 118 is con to left; In thisway, trains approaching relays of signals 8 and 5.

Also, if a. train is. on the Sllblt trackfse'tion 'g, the lock magnet L may be immediately energized by operating the push button.

These features of the operation are similar I to those already explained in connection 7} .ment in both directions.

Suppose, now, a train is approachingthe 7 switch from the left, that is,-'is traveling from left to ri ht, in the direction indicated by the arrow When this train is'in the .track sections 0, (l, e or f, the lock magnet L cannot be energized until after the inter-' val' for which the relayxT is set: When this train has passed the switch; howeveniit no longer prevents energizaticn of the lock magnetL, because of the auxiliary circuits. established b the energizntion of the stick relays 5 S and In the caseof the relay S for example, when thisrelay is energized, the wire 121 is connect-ed direct to Nfso that the lock magnet L may-be energized, although con-' tact 123 or contact 1250f the track rela 's of the track sections hand are open. is previously explained, the stick relays is energized when a ,train passes the. signal 8 traveling in the d'irection 'of -t'rafiic govflied byithat'signal, that is, from left to ight, but is. not .ener ized when a train travels in the opposite irection. The same features of control apply to train movements in the opposite direction from rightthe switch from either direction, prevent a 1 release of its electric look, but trams recedmg from the switch in either direction, do

not prevent such release. It is, of course,

evident that after a trainhas passed the switch and is traveling away from it, there is no longer any occasion toprevent open- 5 is substantially the same as that illustrated in Figs. 3 and 4, with the difference that the control exerted upon the lock magnet L by trains approaching'the switch within certain limits, is obtained from the line For example. the lefthand portion ot the energizing circuit for lock magnet L, comprising wires 106, 120, etc., instead of being taken'through the several front contacts 116and 114 and 111 of the track sections 0, (I and e, as in Figs. 3 and 4, is taken through front contact 150 of line relay H, a shunt forthis contact being established when stick relay Sis picked up. This modified construction 1 there are no track circuits.

obviates the need of extra line wires for any long distance along the track, but may result in extending the limits of control for the lock magnet L further than necessary with certain locations of the siding, as shown in Fig. Referring to Fig. 5, the line relay H is dropped, as soon as a train enters the stretch of single track, that is, referring to Fig. 3, passes signal 2. Evidently this limit of a control is longer than necessary for safety, and may cause useless delays. In other respects, the circuits shown in Fig. 5 are the same as those in Figs. 3 and at and have been given the. same reference numbers.

Fig. 6 illustrates another modification -which is adapted for the protection of a switch lock near yard limits or the entrance to unsignaled territory, or the like, where To illustrate the nature of this modification, I have shown it applied to a stretch of single track over which traflic moves in both directions, but it will be evident that the same scheme of control may be applied to a stretch of doable track. Referring to Fig. 6, it is assumed that the siding SD of the switch to be protected is located near the first signal K of the block signal territory, the territory to the right of said signal K being assumed to be yard limits or other territory not provided with track circuits. The block guarded by the signal K is divided into track sections n, 0 and p having track relays 151, 152 and 153 so as to provide a short track section 0 at the entrance to the sidin'gs SD for the urpose previously explained. A signal it governs traffic in the same direction as the signal K, and an op posing signal M governs trafiic in the opposite direction.

The controlling circuit for signal K, in addition to its control in the usual way by the track relays 151153 of the track sections protected thereby, is also broken at the normall button- B when said push button is operated, and at the switch box contact 98 when the switch is opened. Similarly, the com trolling circuit for "signal M is taken through the normally closed contacts 100 of the push button PB and the switch box contact 98. These controlling circuits are shown in simplified manner to avoid complication.

When a train is on the short track section 0. the lock magnet li may be energized when the push button PE is operated by a circuit running from B, push button contacts 102. .wire 157, back contact 158 of track relay .152. wires 159 and 160, and lock magnet L to N. In this way a quick release of the electric lock may be'obtai-ned when a train pulls up to the switch It a train is on the siding, and itis desired to open the switch,

closed contacts 100 of the push the lock magnet L cannot be energized until after the lapse of time for which the time element relay T is set. Release of the lock under these conditions is not dependent upon the location of trains on the main track, as in the revious modifications. This ditierence 1s occasioned by -the fact that no track circuits exist to the right of the signal K, so that there is a way of telling when a train is approaching within a dangerous distance from the switch. The time clement relay- T is set into operation when the push button is operated in the same ay as already describcd, and after the time interval has elapsed, contacts 40 of relay T close and establish an energizing circuit for the lock magnet L running from it, contacts i wires 161' and 160, and lock magnet L to N. This modified arrangement shown in Fig. 6 permits the safe control of switch locks near the end of block signal territory. Except.- whcre a train is about to enter the siding, the release of this switch lock cannot be obtained until after a short interval of time, but since the signals, as K and M, governing tratiicon the main track past the switch are put to stop at the beginning of this time inlcrval. full protection is obtained. The same arrangement is applicable to any case where it is not. desired to provide an overlap beyond the signals nearest the switch governing traflic on the main track.

According to the present block signaling practice. with which I am familiar, electric switch locks are sometimes used for distant switches near interlocking towers or stations, and the lock is controlled by the operator at said tower or ofiice; but so far as I am aware, it has not been heretofore proposed to provide a switch lock controlled automatically by train movement and manipulated by the trainmcn at the switch, because known ways of governing electric locks have not permitted it to he released when safe to do so, whileat the same time preventing its release in the face of an ap- .proaching train.

The present invention, it. will be observed, satisfies these conditions requisite to proper protection of switches, the switch lock. being controlled in such a way that it may be released and the switch opened under any one of the. contingencies occurring in practice, provided that conditions exist or have been set up to prevent a train running'into the switch.

While I have shown and described various modifications adapted for both single and double track roads, it should be understood that this specific arrangements of circuits and devices are merely illustrativeot the nature and principles of the invention and may be modified or combined by expcdients fam iar to those skilled ill tilt. art, so as to conform to the varying requirements found in practice. I desire to have it under- Letters Patent of the United States is 1. In asystem for protecting an outlying stood, therefore, that my invention is not limited to the specific. constructions and arran ements shown and described, f

I hat I claim and. desire to secure by switch in block signal territory, an electric lock. a normally open releasing circuit for said lock, an electrically operable time ele- 1e anent release adapted to close a brake in said circuit after the lapse of a time interval, and manually operable circuit controllingmeans. at theswitch for initiating the operation of said relay and forsimultaneously goverir ing signals to block train movements over the switch] 2. In a system for protecting anoutlying switch in block signal territory, an electric lock, a track circuit adjacent to the facing points of the switch, a releasing cir'cuit for said lockincluding a back contact of the track rclayof said track circuit, and a manna ally operable circuit controller at the switch for closing 'saidreleasing circuit at another point In a block signalsysteln for railroads having outlying switches, an electric lock for each switch acting when deenergized toprevent opening thereof, a circuit controlled by track circuits near the switch for ener:

giz ing said lock, another circuit for en'er gizing said lock, a normally deenergiz ed time element relay adapted when energized to close a break in said another circuit,

after the lapse of a time interval, and manually operable means for determining closure of said circuits and for simultaneously causing the blocking of train movement over the switch.

4. In a system of the character described,

I an electric look, a plurality of normally open releasing circuits for said lock governed respectively by a track'circuit adjacent to the switch and a time element relay, and manually operable circuit controlling means adjacent; to theswitch for closing said circuits.

5. In a system for protecting outlyin switches, an electric switch lock controlling the switch, a short track circuit at the facing points of the switch, and manually operable' means at the switch responsive to the presence of a train on said track circuit for permitting release of the lock, whereby the. switch may be unlocked and opened without delay to' permit a train on the main track to enter the siding. a

6. In a system for protecting outlying switches in block signal territory -on stretches of single track, an electric lock controlling each switch, a track circu'n controlled means responsive to the direction of movcmen'tof the trains over certain portions of the track on opposite sides of the switch for governing the release of said release.

lock, whereby the trains approaching the switch from either direction will prevent release of the lock while the trains receding from the switch will not prevent such 7. In a' system forprotecting outlying switches in block signal ten'itory on stretches of single track, an electric lock controllingeach switch," an energizing circuit for Y the lock controlled by certain 7 track circuits at one side of the switch,'and means eifective when a train moves over said track circuits away from the switch for establishing said energizing circuit independently of its,track circuit control.

8. An electric switch lockfor outlying switches having three independent energize ing circuits, manually operable circuit con- .trollin'g means for determining the closure of said" circuits, one of the circuits being governed by certain track circuits on one Y side of the switch, another circuit by. 'a short track circuit opposite the facing points of the switch; and the third circuit by a time element relay, andmeans whereby said time element relay is set int'ooperation when said circuit controlling means is actuated.z. 9 An electric lock for outlying switches, anenergizing circuit therefor, an electri-Z cally operable time elementrelay for closing said circuit, a signal governing traffic on the main track past said switch, and manually operable means at the switch for. causing said signal to give its stop indication and for setting said time element relay into operation. 7 M 10. In combinationv with an outlying switch in block signal territory,- a manually operable locking means for said switch, an electric lock adapted when deenergize'd to prevent operation of saidvlocking means, an energizing circuit for saidlock, signals governing trafiic on. the main track past the switch, and having controlling circuits, and a manually operable circuit controller at the switch for breaking said controlling circuim 4 and for simultaneously closing the releasing circuit of the electric lock.

11. In a system for protecting outlying switches in block signal territory, an electric l ck for preventing unlocking of the switch 1 a releasing circuit for said lock governe by track circuits adjacent to the switch, an alternative releasing circuit for the lock, a time element'relay for closin the alternative circuit at one point, and a manually operable circuit controller for simultaneously closing a break in said releasing circuits and for initiating the operation'of the time element relay.

12. In a system for protecting outlying switches in block signal territory, an electric lock controlling the manipulation of the switch, aplurality of releasing circuits for said lock, one governed by track circuits '05 electric lock, hand-operated circuit controladjacent to the switch, a time element relay governing another relay circuit, and a short track section at the facing points of the switch governing a third releasing circuit,

signals governing traflic over the switch and having control circuits, and a manually operable circuit controller for opening said control circuits of the signal, initiatin the operation of the time element relay, and

1 closing a break in each of the releasing circuits.

13. In a system for protecting outlying switches on stretches of single track, an electric look, a releasing circuit governed by a track circuit on' one side of the switch, and means for independently governing said releasing circuit when a train traveling away fromthe switch occupies said track circuit. 14. A system of switch protection for single track railroads,.comprising, an electric lock, areleasing circuit therefor, and means associated with track circuits on one side of the'switch for governing the releasing. circuit dependent on the direction of move ment of trains; 15. A system for protecting switches on single track railroads comprisin ,.the combination with-track circuits'eac having a track relay, a switch, signals governing traf-- fic in both directions towardthe switch, an electric lock, and a releasing circuit for said lock'in'cluding front contacts of said track rela s, shunt circuits'for said front contacts of t efltrackrelays .on oppositesides of the switch automatically closed by trains mov.- ing away from theswitch, and ahand-operated' circuit "controller at the switch for closin said releasing circuit. 1.6. n .a signal system, an outlying switch,

a switch box connected to the switch points, track circuits on one side of the switch and eachhaving a track relay, 'a, signal govern- ,ing'trailic over theswitch and having a con-' trol circuit governed by said track circuits,

and by'contactsof the switch box, an electric lock .for the switch, a hand-operated circuit controller at the switch for breaking said control circuit, and a time element relay governing said lock and set into operation by the actuation of said circuit controllers. 17. In a system of the character described, the combination with anoutlying switch and a short track circuit opposite-the facing point of the switch and having a track re-- lay, an electric lock, and an energizing cir cuit. for said lock including a back contact for said track relay. I

18. In a signal system, the combination withan outlying switch in a block signal territory, an electric look, a signal -governing traffic over the switch, a control circuit for the signal, a r'cleasingcircuit for the erninfg traffic .over the switch, a control cirling means for simultaneously interrupting saidcontrol circuit and closing a break in the lock releasing circuit, and a switch box connected to the points of the switch for opening another break in said' control circuit when the switch is shifted from its normal position. v

19. In a system for protecting outlying switches on single track railroads, the combination with a manually operable switch lock, an electrically operable device for. preventing release of said lock, and means de pendent on the direction of movement of trains for controlling the operation of said device. I

20. In a single track block signal system, the combination with an electric lock for an outlying switch, a releasing circuit for the lock, and means including a stick relay for governing the releasing circuit dependent 35 upon the direction of movement of trains.

' 21. In asystem for protecting outlying switches, an electric lock, the normally opened releasing circuit for the look, a normally deenergized electrically operable time element device-adapted to close said circuit after the lapse of a time interval, and circuit controllingmeans at the switch for initiating the operation of said time clement device. 22-. In a system forprotecting outlying switches in block signal territory, a manually operable switch lock, an electrically operable device forpreventing release of said lock, a time element relay adapted to permit energization of said device and release 'of'saidlock after the lapse of a time interval, and separate manually operable circuit controlling means attheswitchfor initiat-X ing the operation of the time element relay.

- 23. In ;a system of the character described, the combination with an outlying switch and an electric lock therefor, a-normally inactive electricall operable time element device for controlling the release of said lock, an energizing circuit for the time element device, and a spring-return push button lo-' cated adjacent to theswitch for closing said energizing circuit.

24. Means for governing electric locks of outlying switches comprising, a"manually operable circuit controller, an electrically operable time element relay, asign al gov-' cuit or said signal, and a track circuit controlled releasing circuit for the lock, the operation of the circuit controller simultaneousl interrupting said signal control circuit, c osin'g a break in the lock. releasing circuit, and initiating the operation of the time element relay. v

25. In a signal system for single track railroads, an outlying switch, an electric'- lock therefor, signalsi'governingtcn l'fic' in "both directions toward the switch, governs gb' ing circuits'for' the signals, a releasing circult. for. the lock controlled by the track the lock releasing circuit,

circuits on both sides of the switch, and manually operable circuit controlling means for interrupting said-signal control circuits and for simultaneously closing a break in 26. In a system of the character descril ed,

the combination with an outlying switch in block signal. territory, 'manually' operable locking means for the switch, an electrically V operab e de vice including a lock electromaglnetforpreventing operation of said ng means unless saidlocklelectro-magnet is energized, an energizing circuit for the'lo'ck electro-magnet, a signal governing trailic over the switch, a control circuit for the signal, and circuit controlling means for simultaneously interrupting the: signal control circuit and closin -a break in the energizing circuit for *t e rlock electromagnet. a

27. In a s stem. for protecting "outlying switches in b ock signal territory, manually releasable locking means for the switch including'an electro-magnet adapted when deenergized to prevent release ofsaid locking means a plurality of energizing circuits for said electro-magnet, a time element device for controlling one of said energizing circuits, another energizing circuit being controlled by track circuits on one-side of the switch, a; signal governing trafiic toward the switch, a control circuit for said signal, a switchbox connected to the switch points for interrupting said control circuit when theswitch is displaced .from its normal position, and a manually operable circuit controller. actingwhen operated to simultaneously interrupt said control circuit, initiate the operation of said time element device, and close a break in the track circuit controlled energizing circuit for said electro: magnet. Y 28. A system for controlling electric lock of outlying switch on single trackrailroads in which trains within a limited distance of the switch and traveling toward it maintain the electric lock in the locked condition, and

in which trains within a limited distance of the switch and traveling away from it leasing circuits for said lock governed by, said first mentioned means.

30. In 'a single track block signal system, the'combination with an outlying switch and an electric lock therefor,-a signal governingtraflic awayfrom said switch, and means as- '-sociated with said signal and operated'a-utomatically by a train traveling in the direction of trafiic governed thereby for controllihg the. release of said electric lock.

31. In a system of the character described, a switch, an electric lock for the switch, an energizingcircuit for said lock governed by a plurality of track circuits on one side of the switch, and means including a stick relay controlled by two adjacent track circuits of said plurality for independently determinin the release of said lock.

32. cans for protectingoutlying switches in block signal territory comprising, a switch box connected to the switch points, electricallycontrolled and manually operable locking means for said switch, a lock releasing circuit adapted when closed to permit manual operation of said locking means, a signal for governing'trafiic over the switch, a control circuit for the signal governed by said switch box, and a push button havin normally closed contacts included in sai control circuit, and normally open contacts for governing tlie lock releasing circuit.

- 33. In a system for-protecting outlying I switches in blocksignal territory equippe with the usual track circuits, the combine-l tion with two signals governing trafiic to- Ward the switch and automatically controlled by the intervening track circuits, a control circuit for said signals adapted whenever interrupted to cause said signals to indicate stop and caution respectively, electrically controlled locking means for the *switch, a releasing circuit for said locking.

means controlled by at least all of the track circuits between the switch and the signal farthest therefrom, slow acting means adapted to permit release of the'locking means after an interval of delay independently of said releasing circuit, and manually operable means at'the switch for interrupting said control circuit, for'closing a break in said releasing circuit, and for initiating the operation of said slow acting means.

3 In a system for protecting outlying switches in bloclcsignal territory, two signals governing-traffic toward the switch and having a control circuit adapted if inter rupted-to cause said signals to indicate sto and'caution respectively; a'swi'tch circuit controller connected .to the switch points and having contacts opened if the switch is displaced from its main line position, said control circuit including said contacts; manually operable and .electricall controlled locking means at theswitoh finpre-- venting movement ofits points; a releasing circuit adapted if closed to permit operation of said locking means to unlock the switch, said rele'asin circuit being controlled at least by all o the track circuits between the switch and the signal farthest therefrom'and bg' one track circuit in the rear of said fart 'est signal; an electrically operaible time element device adapted to permit release of said locking means after an interval of time i signature.

leasin circuit, and initiating the operation of sai time element device. in In testimony whereof I have aiiixed'my SEDGWICK N. WIGHT. 

